The current $1-$year yield on a treasury bill is $2\mathrm{.}5\%$ and the current $1-$year yield on a BB$-$rated bond of equivalent risk to a prospective borrower is $6\mathrm{.}75\%.$ The loan has a marginal probability of default in year $2$ of $5\mathrm{.}35\%.$ What is the cumulative probability of default over the $2$ years?